Nicolette S. Harmon Week 2

Contents

Methods

The first step I did was to to determine whether the parental organisms were heterozygous or homozygous. This was done through self-pollination.

The next step was to determine which alleles were dominant and which were recessive in the parental generation, so it was necessary to test-cross all possible combinations of the four parents.

By this time, new colors had appeared in the F1 generation. To determine which colors were alleles it was necessary to self-pollinate an offspring of each color. This process carried over into the F3 generation when it was determine that Red, Green, White, Blue, and Yellow were true-breeding alleles.

With the additions of the yellow and blue alleles, all of the true-breeding alleles were crossed together in different combinations to determine dominance amongst all of the allels.

The colors Purple, Orange, and Black were not true-breeding which meant that they were heterozygotes. By this time it was clear that White was recessive to all of the other alleles, so these 3 colors were crossed with White to determine which alleles composed each color.

Results

Self Pollination of Original 4 Organisms

In the Green-1 X Green-1 cross, all of the offspring were green.

In the Green-2 X Green-2 cross, there were 23 offspring 10 were green, 9 were yellow, and 4 were blue.

In the Red X Red cross, there were 24 offspring 20 were red and 4 were white.

In the White X White cross, all of the offspring were white.

True-Breeding Organisms

The Blue offspring in the F1 generation of the G2xG2 cross were self-pollinated, all of these offspring were blue.

The Yellow offspring in the F1 generation of the G2XG2 cross were self-pollinated, all of these offspring were yellow.

The Red offspring from the RXW cross were self-pollinated, there were 25 offspring 22 red and 3 white offspring.

The Red offspring from F1 RXR cross were self-pollinated, all of these offspring were red.

One offspring from each of the steps 1,2,4 was saved in the greenhouse sidebar as a true-breeding organism.

Determining Dominance

The true-breeding Yellow was crossed with the true-breeding Blue, all of these offspring were green.

The Green offspring in the F1 generation of the G1XG1 cross was crossed with the true-breeding Red, all of these offspring were black.

The true-breeding Yellow was crossed with the true-breeding Red, all of these offspring were orange.

The true-breeding Red was crossed with the true-breeding Blue, all of these offspring were purple.

The true-breeding Green was crossed with the true-breeding Blue, all of the offspring were green.

The true-breeding Green was crossed with the true-breeding Yellow, all of the offspring were green.

The White from the WXW was crossed with the true-breeding Green, all of the offspring were green.

The true-breeding White was crossed with the true-breeding Yellow, all of the offspring were yellow.

The true-breeding White was crossed with the true-breeding Blue, all of the offspring were blue.

The Alleles of the Heterozygotes

Purple was crossed with White to produce 10 red and 13 blue offspring.

Orange was crossed with White to produce 11 yellow and 11 red offspring.

Black was crossed with White to produce 14 green and 13 red offspring.

Conclusion

To figure out how color is inherited in flowers, I self-crossed the four starting organisms that the program gave me. These four organisms were Green-1 which produced all green offspring, Green-2 which produced yellow, blue and green offspring, Red which produced red and white offspring, and White which produced white offspring. There are 5 different alleles that were discovered through the various crosses. The Y allele produces the color yellow, the R allele produces that color red, the G allele produces the color green, the B allele produces the color blue, and the W allele produces the color white. The white allele is recessive to all of the other alleles. The green allele is co-dominant with the red allele and dominant to the blue and yellow alleles. The red allele is co-dominant with the green, blue, and yellow alleles. The yellow allele is co-dominant with the blue and red alleles. The blue allele is co-dominant with the red and yellow alleles. The genotypes for the red allele are RR and RW since white is recessive to all of the other alleles. The genotypes for green are GG,GY,GB,YB,and GW. The genotypes for the blue allele are BB and BW. The genotypes for the yellow allele are YY and YW. The genotype for the white allele is WW. The color purple is produced from the genotype RB, the color black is produced from the genotype GR, and the color orange is produced from the genotype YR, since these colors are formed through co-dominance they can never be true-breeding colors. From this information I was able to conclude that the genotypes of the starting four organisms were Green-1: GG Green-2: BY Red: RW White: WW. Mutations teach us how certain traits were introduced into a population and which ones caused this event to happen. No new colors were discovered from mutating the flowers since there were already a variety of colors that came from co-dominance. It is easier to mutate from color to white since white is recessive to all other colors.
This lab was a great way to practice reasoning and other scientific skills since it was up to us to figure out what to do, as opposed to being told what to do through steps. Having no set instructions gave me the freedom to manipulate the program in different ways to give me the results that I was searching for, the program was easy to use and gave me instant feedback about the methods that I was trying out. I feel that this experiment was extremely helpful and good practice for whats to come in this course.